The search for new emergent states has been the frontier of quantum materials research and often achieved by tuning competing or cooperative interactions among the spin, charge, orbital, and lattice degrees of freedom [1]}, [2]}, [3]}. Dimensionality is a unique and critical control parameter for this purpose, since quantum confinement may enhance electronic correlation [4]}, [5]}, lead to stronger fluctuations [6]}, [7]}, and trigger exotic phenomena beyond mean-field theory [3]}, [9]}. While the effects of dimensionality can be revealed by driving a system, for example, from the two-dimensional (2D) limit to the three-dimensional (3D) limit or the other way around, drastic changes do not necessarily take the full crossover to arise. Distinct behaviors and phases could readily occur when one more atomic plane is added to a 2D quantum confinement structure, e.g., going from a monolayer system to a bilayer system [10]}, [11]}, [12]}, [13]}, [14]}.
